Combustion indicator



Sept. 24, 1929. M. ERNST ET AL COMBUSTION INDICATOR Filed July 26, 1926 w "W w #L 6% 66 w 656 /6 5 1 5 M666 6 6 6 1 66 6 66 Patented Sept. 24, 1929 UNITED STATE-S MATTHEW ERNST AND HARRY B. H'OLTHAUS, OF CHICAGO, ILLINOIS COMBUSTION INDICATOR Application filed July 28,

Our invention relates to improvements in indicators and is illustrated as used in connection with furnaces, to. indicate the conditions of combustion therein.

Our device is illustrated as adapted for use in connection with instrumentalities for influencing the indicator upon either of two conditions, namely, upon .the translucence of the gaseous and suspended products of combustion, such as, for instance, smoke as is found in a smoke stack, or secondly, upon heat conditions in several locations which may be in different parts of one furnace or in different furnaces.

In the disclosure is shown one compact and efiicient system which has as a part thereof, this improved indicating device from which a multiplicity of conditions may be readily determned. This system embraces an indi- 2 cator which is sensitive to very minute variations and which has as an important feature a large and readily visible dial, the reading of which may be determined promptly from a distance without difliculty.

This improved indicator is disclosed as a part of a system in which means are provided which will cause variations of current in a circuit depending upon the translucence of the smoke as found in a stack of a furnace. This type of influencing means embraces a circuit which contains in series a source of current, for instance, a battery, a galvanometer and a variable resistance unit, the latter being of a special type and is one which varies according to the presence or absence of light. A selenium cell may be used for this purpose. The light responsive resistance unit is adapted to be placed so as to receive a beam of light, the source of which is on the opposite side of a column of smoke and which will, by virture of the light obstructing qualities of smoke given ofl as a result of imperfect combustion, vary the resistance accordingly. It is to be noted that this type of influencing means is essentially a regulator for the current and one which necessitates a battery or other suitable source of current to be placed in the circuit.

A second t pe of influencing means is also illustrated w ich influences the indicator upon varying heat conditions and is shown as 1926. Serial No. 125,111.

current generating thermo-couples. A plurahty of these are laced in various locations so that they will e responsive to and generate various amounts of current according the heat conditions in their particular locaions;

Switches are shown placed in the two Oil cults so as to render it possible to connect for operation the indicator upon conditions of the smoke in the smoke stack or upon conditions of heat as found in the Various locatio'ns in the furnaces. The two circuits are connected to the same galvanometer, which is of a particularly sensitive type so that its armature may move sufficiently accordin to the slight o5 variations in current in the rst circuit as effected by the slight changes in the selenium cell caused by the extent of'the obstruction of the light by the smoke, and also one which is capable of operating sufiiciently by a' small amount of current such as is generated in the thermo-couples.

The indicator contemplated in this invention is one of great usefulness due to its high degree of efficienoy and to its construction of dial, the latter of which is of such nature and size that the readings thereon are readily de terminable at a glance and from rather distant locations.

One of the special features of this indicator is that it is provided with a darkened translucent wall adapted to receive a spot of light. the position ofwhich indicates conditions to be determined, this wall being adjacent a brightly illuminated translucent wall on which is marked one or more graduated scales. The contrast between the highly illuminated wall and the darkened wall due to their proximity renders a small spot of light on the darkened wall easier to see. Thus it may be seen that this particular type of indicator is highly desirable where a high degree of visibility is an important factor.

The operation of the device will be more readily understood by the following detail description when considered in connection with the accompanying drawing throughout which similar reference characters represent corresponding parts.

Referring to the drawings Figure 1 shows the entire system including the two indicators, two kinds of influencing means and electrical circuits connecting them to form one system. This figure is partly in cross-section and partly in perspective, the connections and the electrical controls being shown diagrammatically; and,

Figure 2 is a perspective view of the end of the spotlight lndicator with the end wall removed so as to reveal the partition and the electric light for the illuminated compartment.

Referring to Figure 1, 10 represents a smoke stack shown in the drawing as a brick structure but which may be any passageway through which the smoke or gaseous products of combustion pass after combustion takes place. Numeral 12 shows a cross-sectional thickness of the wall forming the passageway 13 through which the smoke passes. 14 represents diametrically oppositely aligned openings through the wall 12 which are adapted to receive tubes 15. On the outside of the stack 10 and placed over one of the openings 14 is the semi-spherical reflector element which is positioned in air-tight relation on the outside of the wall 12 so as to form a closed chamber and which has mounted therein opposite the opening 14 an electric light 17 secured in a suitable socket connected by the wires 18 to a source of current, and adapted to be regulated by the rheostat shown at 19. At the outer end of the tube 15, which is at the opposite side of the stack, is secured a metallic casing 11 which forms a closed chamber, and which is mounted on a suitable bracket 23 and insulator 24 and has contained therein a light responsive resistance unit 22. This resistance unit is placed opposite the mouth of the opening 14 and in alignment with the light 17 so as toreceive the rays of light therefrom. 20 and 21 are glass housings of which 20 may be clear, or a color screen. The closed chambers formed by the casing 11 and the reflector 16 are connected by pipes 26 to a liquid sealed air intake 27 which comprises a receptacle, containing liquid, with the air inlet pipe 29 which extends below the liquid level, pipes 26 communicating with the sealed intake above the level of the liquid. The purpose of this arrangement is to prevent the escape of smoke through the openings 14 which would interfere with the functioning of the light sensitive resistance unit and also to provide a clear, transparent atmosphere in these openings, which is accomplished by the inward flow of air drawn in from the sealed intake caused by the draft in the stack.

The light responsive resistance unit is connected by wires to the switch 30'which form with the wire connection 25, variable resistance unit 31, battery 32, connecting wire 25, galvanometer 39 and wire 25, a complete circuit by which the galvanometer is influenced according to variations of resistance due to the amount of light passing through the stack. Wires 33 and 25", together with switch 34, form the connection for the recording indicator 35 which has a rotary dial 36 and electrically influenced marker 37. When it is desiredto obtain a permanent record of the conditions existing in the stack, this last named indicator is connected by the switch 34 at which time it will operate simultaneously with the spotlight indicator. The spotlight indicator is preferably composed of a boxlike casing 38 in which the galvanometer 39 is mounted. The galvanometer is composed of a base 40, permanent magnet 41, armature 42, wire 43 and mirror 44. This mirror is very small and is adapted to deflect a concentrated beam of light due to the fact that it is mounted on and movable with the wire 43 which holds the armature and any movement of the armature caused by the variations in current will cause a corresponding movement of the mirror. At the opposite end of the boxlike member 38 is placed an adjustable light designated generally at 45 which consists of an adjustable base 49, a light housing and reflecting member 46 containing the electric light 47 and the tube 48. The tube 48 is placed in front of the light bulb and is adapted to concentrate and direct the beam of light on the mirror 44. The electric light 47 is supplied with current through connecting wires 51. It can be readily understood that the deflected beam of light will fall on the darkened wall in a location depending upon the amount of deflection of the galvanometer as caused by the current passing through the circuit and in this manner indicate the conditions to which the connected influencing means is subjected. 52 is a partition which is better shown in Figure 2 for forming two compartments in the boxlike member and is placed in an inclined position so that its upper end may intersect the end wall of the boxlike member. The two compartments are designated 53 and 54, 53 being darkened and provided as at 55 with a translucent glass end wall. Compartment 54 is adapted to be brightly illuminated by means of electric light 66 positioned in socket and connected to a source of current by the wires 51, and is provided with an end wall of translucent glass 56 on which one or more graduated scales are placed near the upper edge. A spacing element 57 is interposed between the two glass end walls 55 and 56 so that the light from illuminated wall 56 may not pass through the adjacent edges and disturb the dark appearance of wall 55. 64 is a hood over the darkened wall mounted-ina manner to shadow it and to maintain its darkened condition.

The second circuit of our system is made up to include the same indicator, being con nected to the same galvanometer but omitting the battery 32 due to the fact that the current is generated in this circuit from one of the thermo-couples shown at 61, 62, 63. These thermo-couples are so connected that by movement of the switch 60 any one may be selected as a source of current. Connecting wires 25, the switch 59 and wires 25 serve as a connecting means to complete the circuit which joins the first circuit by attachment to wires 25, 25", but in a manner to exclude the source of current which is the battery 32, the same not being necessary in this circuit. It may be seen from this disclosure that our invention is capable of a very useful a plication in determining conditions of com ustion at various sources.

The first circuit above referred to embraces a device which will influence the indicator when the switch 30 is in on position and the switch 59 is in off osition causing'conditions in the stack, w ich are re resentative of conditions of combustion, to indicated in a readily visible manner, or if desired, by permanent record in a place remote from the ocation of the influencing mechanism, or if it is desired to determine the conditions of combustion as indicated by temperatures, switches 30 and 59 may be moved in reverse order and by the mani ulation of the switch 60, the indicator will responsive to current generated by the thermo-couples in any of the selected locations.

It is to be understood that in the above description of operation where the word indicator is used that either the indicator designated generally at 38 as operating alone may be intended, or the recording indicator 35 may be included to o erate in conjunction with the first indicator, 0th of these indicators bein influenced by the same current variations an the only diflerence residing in the type of indications they make.

In the drawings two scales are shown which may be properly graduated for the two ty es of influencing devices, and it is to be un erstood that the location of the li ht spot is to be considered in connection wit the proper scale in reading the indicator, depending upon the type of influence device which is connected for operation. Also the scales are preferably provided with a centrally located zero mark to represent a normal condition and deflections on either side wilLrepresent differences above or below-normal accordingly. It isto be understood that any number of scales may be placed on the illuminated wall 56 in the event that it is found necessary due to the diflerence in degree of deflection caused by the current from various sources. This disclosure is largely diagrammatical and merely stands for a representative pe of our invention. There may be various 0 anges without departing from the vention, and it is our intention to include irit of the mequivalent elements which come within the scope of the appended claims.

We claim:

1. .In an indicator, a boxlike member having a darkened wall ortion and an illuminated wall portion ad acent one another, said darkened wall portion receiving a beam of light positioned accordin to conditions to be indicated and said illuminated portion presenting a highly visble graduated scale.

2. In an indicating device, a boxlikc member containing indicating means, said box having adjacent portions comprising a darkened translucent "wall and an illuminated translucent wall, said illuminated wall having a graduated scale thereon, said darkened wall adapted to receive a beam of light from said indicating means directed according to conditions to be indicated and in close proximity to said scale.

3. In an indicator, a box-like member having a partition therein forming two compartments, adjacent walls of said two compartments each having a translucent window forming a wall of the box, one of said windows having a graduated scale thereon, and means within the compartment thereof for illuminating the window and scale, said other compartment being constructed to exclude external light, and having means therein for directing a beam of li ht on the translucent window thereof in indicating relation with said illuminated window and scale, and moving the beam of light in accordance with conditions to be indicated.

4. In an indicator, abox-like member having a partition therein forming two compartments, adjacent walls of said two comartments each having a translucent window orming a wall of the box, one of said windows having a" graduated scale thereon, and means within the compartment thereof for illuminating the window and scale, said other compartment being constructed to exclude external light, and having means therein comprising a source of 1i ht and movable light reflecting surface for directing a beam of light on the translucent window thereof in associated relation with the illuminated window and scale, said light reflecting surface being movable in accordance with conditions to be indicated.

Signed at Chicago, Illinois, this 20th day of July, 1924.

MATTHEW ERNST. H. B. HOLTHAUS. 

